Welcome to the Onshape forum! Ask questions and join in the discussions about everything Onshape.

First time visiting? Here are some places to start:
  1. Looking for a certain topic? Check out the categories filter or use Search (upper right).
  2. Need support? Ask a question to our Community Support category.
  3. Please submit support tickets for bugs but you can request improvements in the Product Feedback category.
  4. Be respectful, on topic and if you see a problem, Flag it.

If you would like to contact our Community Manager personally, feel free to send a private message or an email.

Any hints & tips on parametric design "best practice"? (in Onshape)

john_smith077john_smith077 Member Posts: 109 ✭✭

I am new to parametric design. I keep finding that when I go back and tweak my dimensions, that I am breaking the design.

Can anyone give me any tips on do's and don'ts / best practice of designing things to be re-sized.




  • colemancoleman OS Professional Posts: 244 PRO
    edited January 2016
    Make sure the sketch is fully defined (black). 
  • dennis_20dennis_20 Member Posts: 88 ✭✭✭
    Go through ALL the tutorials and help files you can find.  Pay attention to the techniques, not just the lesson objectives.

    You might be breaking you designs because you don't have your sketch lines properly constrained.  For instance you might have drawn lines that appear to be vertical or horizontal, but they are not or they are not constrained to be V/H.  Not understanding and utilizing sketch constraints is probably the single biggest thing missing from a newbie's use of parametric software.  Also, learn where to put sketch dimensions so they give you a constraint.  For instance, pick two parallel lines for a dimension instead of the line connecting them or the endpoints of the line connecting them.  If you pick the connecting line or its endpoints you'll hold that line to whatever dimension you assign, but the parallel lines might now need an additional constraint (which just introduces a lot of extra and confusing work).  However, if you pick the two sides your dimension will hold those lines parallel and separated by the distance of the assigned dimension.

    You might know exactly what you intend with your sketches, but unless you take advantage of the automatic and manual constraints the software doesn't know.  Further, knowing these constraints puts you in the position to control when they are or are not applied.  For instance, if you sketch a four sided figure one time you might want it to be a rectangle, but another time you might want it to be a trapezoid.  The rectangle is easy to define if you take advantage of the automatic constraints, but for the trapezoid you'd want to avoid or break at least one of the orthogonal constraints.  Here's a good fundamental tip:  ALWAYS make your sketches fully constrained (all your sketch lines should turn black).

    Little things like this will go a long way to reducing your frustration and making your designs more robust.  Since you are needing to learn fundamentals of parametric 3D modelling you might also want to expand your learning arena beyond Onshape.  I'm not advocating something other than Onshape for your modelling, just that you take advantage of the huge volume of YouTube videos for SolidWorks.  The techniques are the same.  Another resource you might look into is SolidProfessor (http://www.solidprofessor.com/training-plans/onshape/)

    Glad to see your attitude toward Onshape has changed.  Welcome to the community!

  • NeilCookeNeilCooke Moderator, Onshape Employees Posts: 3,264
    @john_smith077 sign up for some of Cody's webinars on the Onshape home page - he does a great one on design intent that will help you plan and understand best practices for creating robust parametric models. 
  • Marc_MillerMarc_Miller Member Posts: 73 ✭✭✭
    Yes, the design intent webinar had some great tips to think about if you are new to parametric modeling.  The webinars are also recorded so you can watch at your convenience, or again.

  • john_smith077john_smith077 Member Posts: 109 ✭✭
    Yes, those videos are extremely useful. Many thanks   :)

    I have a general question about parametric design:
    If I have a model that is nearly finished, is it better to create a new Sketch or to go back and add stuff to my original sketch?
  • shashank_aaryashashank_aarya Member Posts: 265 ✭✭✭
    edited January 2016
    @john_smith077 Generally it depends on some conditions such as complexity of part, feature tree sequence, feature dependencies etc. In some cases I will prefer to add entities in sketches where sketch and feature dependency will not affect much and model will not crash. Even if it gets crashed it should be easy to repair by redefining the references. But whenever I feel that model could get crashed in such a way that it cannot be repaired, I prefer to add new sketch and feature.
  • 3dcad3dcad Member, OS Professional, Mentor Posts: 2,443 PRO
    I try to think where would I look to modify that certain thing if I come back after a year or so. + give thought to what @shashank_aarya
Sign In or Register to comment.